Thin film transistor-liquid crystal display (abbreviated as TFT-LCD) which has advantages such as small size, low power consumption and free of radiation, develops rapidly in recent years and takes a dominant role in the current panel display market. The main component of a liquid crystal panel is a liquid crystal panel. In manufacturing process of the liquid crystal panel, the design for cell gap and compression resistivity is a key technology of the liquid crystal display and directly affects the quality of the liquid crystal display.
As shown in FIG. 1, a liquid crystal panel includes an array substrate 20′ and a color filter substrate 10′ which are oppositely arranged to form a cell, and a liquid crystal layer between the array substrate 20′ and the color filter substrate 10′. The array substrate 20′ and the color filter substrate 10′ are sealed by a sealant 3. A thickness of the liquid crystal layer (i.e., a cell gap) is mainly controlled by a post spacer (PS) located between the array substrate 20′ and the color filter substrate 10′. According to functions, PSs include a main PS 1′ and an auxiliary PS 2′. The main PS 1′ has a length larger than that of the auxiliary PS 2′, and the main PS 1′ and the auxiliary PS 2′ need to be formed through different processes. A number of the auxiliary PS 2′ is larger than that of the main PS 1′. After the liquid crystal panel is made into a cell, the main PS 1′ may have a certain amount of compression to maintain the cell gap, while the auxiliary PS 2′ has no amount of compression. In a case that the liquid crystal panel is subjected to a relatively large external force, the auxiliary PS 2′ is compressed and functions as a main supporting member.
In practical production, the fluctuation of amounts of liquid crystals filled in respective liquid crystal panels should be considered to ensure the stability of mass production on the production line. For example, a theoretical mass of liquid crystals necessary for each liquid crystal panel is 100 mg. Considering the accuracy of a device for dripping liquid crystals in the production line, a mass of liquid crystals finally inside a liquid crystal panel may range from 93 mg to 107 mg, this fluctuation range of the mass of liquid crystals is called as a liquid crystal margin (LC margin). A main parameter determining a size of the LC margin is a height of the PS. In a case of disregarding other factors, the LC margin should be maximized to ensure the stability of mass production of the production line. An amount of compression of the main PS 1′ determines an upper limit of the LC margin; the larger the amount of compression is, the larger the upper limit of the LC margin is. A height difference between the main PS 1′ and the auxiliary PS 2′ determines a lower limit of the LC margin; the larger the height difference is, the smaller the lower limit is.
If the height difference between the main PS 1′ and the auxiliary PS 2′ is small, the compression resistivity of the panel is strong, but the lower limit of the LC margin increases; the compression resistivity and the lower limit of the LC margin conflict. When developing the products practically, the compression resistivity is ensured at the sacrifice of the lower limit of the LC margin; hence, the process fluctuation in mass production of the products is restricted and the productivity of the production line is greatly affected.